Cutting and replacing a section of cast iron stack

Old 04-30-18, 08:23 AM
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Cutting and replacing a section of cast iron stack

Hello and thanks for any help you can provide.

My 1948 home is leaking from the cast iron stack. One spot about 16" above cellar floor the another a bit above that but before any branching to the upper floors. Will need to remove about 3' of pipe.

Watched a few videos and this seems like something I can accomplish. Hope Depot rents that ratchet pipe cutter to make the cutting easier.


1) Was told I will need to tie off/brace the pipe above the cut or it will all come crashing down on top of me. Can I do this with pipe strap to the joists or will that not be sufficient to support the weight? House has two stories.

2) Is substituting PVC the proper method and are there any negatives to doing it this way? Will that support the rest of the cast iron stack no problem or will the braces need to remain forever??

Any other suggestions or things to watch out for will be appreciated.
Old 05-01-18, 10:15 AM
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No issue with your plan.

Use metal pipe strapping around the elbow as well as the bell ends. You have a few hundred pounds of pipe above you that you'll need to support. Use a couple straps and screw it well into the joists above.

Some of the weight will also be born by upper floor wyes and such.

You'll want to keep those supports in place. The PVC won't support it.

And yes, PVC is easiest - along with 2 no-hub (shielded) couplings.

Just be careful when you use the snap cutter. A 3' section is pretty heavy too, so you'll want someone to help 'catch' it when you cut it.

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